Reading the datasheet: http://datasheet.octopart.com/ADNS-9800-Avago-datasheet-10666463.pdf
Page 13: Path deaviation It seems that a homogenous surface puts down the error to ~1.25 / 1600 inch / inch with an optimum @~0.8 /1600 inch / inch with photopaper and a sensing distance of 2.25mm. All at a relatively low speed (6ips) Combined with a rough syncing (every 2mm) - using a frame capture of the sensor - you shall be able to get pretty high resolution with a minimum of effort. The sensor itself works up to 150ips and 30g, what the resolution and deviation there may be... I dont know. It is - not recommended for new designs, but I am sure there is equivalent stuff out there. best regards julian On Sat, 08 Aug 2015, Julian WIngert wrote: >>> Am 08.08.2015 um 04:00 schrieb EBo: >>>> On Aug 7 2015 5:32 PM, Peter C. Wallace wrote: >>>>> On Fri, 7 Aug 2015, EBo wrote: >>>>> >>>>>> Date: Fri, 07 Aug 2015 17:13:25 -0600 >>>>>> From: EBo <e...@sandien.com> >>>>>> Reply-To: EMC developers <emc-developers@lists.sourceforge.net> >>>>>> To: emc-developers@lists.sourceforge.net >>>>>> Subject: Re: [Emc-developers] research on optical encoders >>>>>> >>>>>> On Aug 7 2015 4:16 PM, andy pugh wrote: >>>>>>> On 7 August 2015 at 12:23, EBo <e...@sandien.com> wrote: >>>>>>>> Possibly, but I cannot tell from the information Renishaw >>>>>>>> published >>>>>>>> in >>>>>>>> that brochure. >>>>>>> I think that the target is a barcode. The head can see enough >>>>>>> barcode >>>>>>> to tell exactly where it is on the code sequence to within one >> bar, >>>>>>> then looks at the absolute position of the bars in the viewing >> area >>>>>>> to work out the rest of the bits of data. >>>>>> I think it is following on the same idea roughly. Looking at the >>>>>> renshaw they claim it can give you 1nm (1e-9m) or 3.9e-8 inches >>>>>> precision. I have no idea how they are pulling that off besides >>>>>> laser >>>>>> interferometry and ring counting. Can you suggest another method >>>>>> that >>>>>> would work? >>>>> AFAIK they dont use a laser, just a bright LED thats pulsed to >> take a >>>>> snapshot >>>>> of the barcode, probably with a rather high resolution linear >> sensor >>>>> array (or >>>>> multiple arrays with pixel interleaving) >>>>> >>>>> Quite high-sub pixel interpolation should possible with such a >> setup >>>>> because >>>>> of all the duplicated edges >>>> agreed with the laser/LED. I would have to study sub pixel >>>> interpolation to see how much additional interpolation you could >> get. >>> You can get really fine results on a theoretical perfect black/white >>> change and the imaging sensor mounted 45deg. of an almost unlimited >>> degree of subsampling. >>> Even with a cheap camera and optics there should be no problem to >>> resolve down to the uM scale. Problem is the speed of such a >> construct. >>> Even with high performance camera systems you have a delay that makes >> it >>> imho unusable in realtime positioning. >>> >>> If you are able to interface the sensor with an FPGA doing the >> realtime >>> analysis - well then you have what renishaw probably has build... >>> >>> What should "relatively" easy to be doable is to add such a slow >> scale >>> to recalibrate the machine position regularly. >>> >>> My first idea was to use a laser mouse sensor, which is easily >>> interfaceable even with MESA cards - there are ones with SPI >> interface - >>> but my application is the calibration of my astronomic mount - which >>> hardly moves more than 1RPD (Rounds per DAY)... >>> >> maybe a somewhat naive question - but how would you deal with vibration >> >> of the cameras/sensors ? gut feeling - if you try to deduce 10E-9 m >> then >> even just environment noise would become a problem or is there some way >> to eliminate that in practice ? >> >> thx! >> hofrat >> >> ------------------------------------------------------------------------------ >> _______________________________________________ >> Emc-developers mailing list >> Emc-developers@lists.sourceforge.net >> https://lists.sourceforge.net/lists/listinfo/emc-developers -- Mit freundlichen Grüßen aus Pinneberg Julian Wingert Hellenkamp 8 25421 Pinneberg Phone: 0170/4516094 Mail: julian.wing...@web.de USt-IdNr.: DE272503212 ------------------------------------------------------------------------------ _______________________________________________ Emc-developers mailing list Emc-developers@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-developers
